1)原式=a(b-c)+b-c=(a+1)(b-c)
2)原式=a(a-b)-2(a-b)=(a-2)(a-b)
3)原式=3(a-3b)+2c(a-3b)=(3+2c)(a-3b)
4)原式=3xy(x+2)-4(x+2)=(3xy-4)(x+2)
5)原式=x^2-xy+3y-3x=x(x-y)-3(x-y)=(x-3)(x-y)
6)原式=x^2(x+2y)-9(x+2y)=(x^2-9)(x+2y)=(x-3)(x+3)(x+2y)
7)原式=(x^2+x)(y+2)-12(y+2)=(x^2+x-12)(y+2)=(x-3)(x+4)(y+2)
8)原式=m^2x^2-m^2y^2+n^2y^2-n^2x^2=m^2(x^2-y^2)+n^2(y^2-x^2)=(m^2-n^2)(x^2-y^2)=(m+n)(m-n)(x+y)(x-y)
填空
()=2ab*6ab^2=12a^2b^3
()=15xy*(-5xy^2)=-75x^2y^3
()=125a^2x^3/(-3ab)=125ax^3/(3b)
补充的
()=24a^3b^2/(-3ab)=-8a^2b
()=125a^2x^3/5a=25ax^3